Develop Reference

ScrollTop not reverting back when scroll to top

Having problems with Scrolltop - have got it to change smoothly when scrolling down, but doesn't revert to the original css when scrolling back up.
I've tried switching the order around but nothing works. Can anyone tell me where my code is wrong?
Thanks
$(function() {
var topblock = $(".topblockfix");
var header = $(".header");
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if ($(window).scrollTop() > $('.topblockfix').offset().top) {
if (scroll >= 250) {
topblock.removeClass("topblockfix").addClass("topblockfix-alt");
header.removeClass("header").addClass("header-alt");
} else {
topblock.removeClass("topblockfix-alt").addClass("topblockfix");
header.removeClass("header-alt").addClass("header");
}
}
});
});

You have a logical mistake in the first if-statement.
You are checking the offset top of $('.topblockfix'). But you remove the class .topblockfix and set it to .topblockfix-alt.
So you need to update your if statement:
if ($(window).scrollTop() > $('.topblockfix').offset().top || $(window).scrollTop() > $('.topblockfix-alt').offset().top) {
or you have to cache the value of $('.topblockfix').offset().top somewhere

Show one div when another div scrolls off screen. Getting unwanted flashes

I would like to show one div (.cu5-topbar) when another div (.cu5box-box) scrolls off screen. The problem is that the the .cu5-topbar div is showing up right as the .cu5box-box div is leaving the screen. That's also causing the .cu5-topbar to flashing for a few seconds while the two divs overlap each other. Here is my code so far:
var scroll_start = 0;
var startchange = jQuery('.cu5box-box');
var offset = startchange.offset();
if (startchange.length) {
jQuery(document).scroll(function () {
scroll_start = jQuery(this).scrollTop();
if (scroll_start > offset.top) {
jQuery('.cu5box-box').fadeOut(400);
jQuery('.cu5-topbar').fadeIn(400);
} else {
jQuery('.cu5box-box').fadeIn(400);
jQuery('.cu5-topbar').fadeOut(400);
}
});
}
https://jsfiddle.net/zgu70p4m/
I would like for the .cu5-topbar div to show up as soon the .cu5box-box div is completely off of the screen and I would like for the .cu5-topbar div to disappear as soon as the .cu5box-box div comes onto the screen.

Try the below, you had not included jQuery in your jsfiddle example.
You also needed to attach the scroll event to the window. Finally the offset needed the elements height added to the total to make sure you where getting the correct position of the end of the element.
var scroll_start = 0;
var startchange = jQuery('.cu5box-box');
var offset = startchange.offset();
if (startchange.length) {
$(window).scroll(function () {
scroll_start = $(this).scrollTop();
if (scroll_start > offset.top + startchange.height()) {
$('.cu5-topbar').fadeOut(400);
} else {
$('.cu5-topbar').fadeIn(400);
}
});
}

Fade repeating after replacing image while scrolling with javascript

I'm trying to replace the logo image in heading of the page when scrolling, with fade effect. It starts working in the correct way, and the image replacement is done but while you continue scrolling down the site, the new logo continues fading.
Here's my code:
$(document).ready(function(){
$(window).scroll(function(){
var scroll = $(window).scrollTop();
if (scroll > 100) {
$(".navbar-fixed-top").addClass("nav-scrolled");
$('#logo').fadeOut('',function(){
$(this).attr('src','Template/images/logo-scrolled.png').fadeIn();
});
}
else{
$(".navbar-fixed-top").removeClass("nav-scrolled");
$('#logo').fadeOut('',function(){
$(this).attr('src','Template/images/logo.png');
});
}
})
})
You can see it in www.ultramarinosvillena.com
How could I fix it?

EDIT: sorry, my mistake - first thinking then posting. ;) One of the conditional statements was triggered with each scroll event - now it will only be triggered once, when the scrolling point is reached.
You should check the nav-scrolled class:
$(document).ready(function(){
var $navbar = $(".navbar-fixed-top"),
$logo = $("#logo"),
currentScroll;
$(window).on('scroll', function(){
currentScroll = $(window).scrollTop();
if ( currentScroll > 100 && !($navbar.hasClass('nav-scrolled')) ) {
$navbar.addClass("nav-scrolled");
$logo.fadeOut('',function(){
$(this).attr('src','Template/images/logo-scrolled.png').fadeIn();
});
} else if ( currentScroll < 100 && $navbar.hasClass('nav-scrolled')) {
$navbar.removeClass("nav-scrolled");
$logo.fadeOut('',function(){
$(this).attr('src','Template/images/logo.png').fadeIn();
});
}
});
});

Stop jquery function on it's running state

I am trying some thing like this
Demo JSFIDDEL
the problem with this code is that it scrolles multiple time when i move the scroll bar up down..
$(document).scroll(function () {
var y = $(this).scrollTop();
if (y > 50) {
$('.mydiv2').show(1000);
} else {
$('.mydiv2').hide(1000);
}
});

Demo
Check the link. You are hiding a div and showing it again with scroll event. You need to add stop(true) in hiding and showing also
if (y > 50) {
$('.mydiv2').stop(true).show(1000);
} else {
$('.mydiv2').stop(true).hide(1000);
}

var y = $(this).scrollTop();
above statment makes multiple scroll because you scrolling up window using code

Div stops at the top when scrolling

I am trying to make a div change class to fixed when it reach the top of the page.
I have this JavaScript code.
<script type="text/javascript">
$(function () {
var top = 200;
var y = $(this).scrollTop();
if (y >= top) {
// if so, add the fixed class
$('#kolonne-v').addClass('fixed');
} else {
// otherwise remove it
$('#kolonne-v').removeClass('fixed');
}
});
</script>
What am i doing wrong?

Demo jsFiddle
JS
$(function () {
var top = 200;
//this should be the offset of the top of your div
//which can be found by doing the following line
//var top = $("#kolonne-v").offset().top;
$(window).on('scroll', function () {
if (top <= $(window).scrollTop()) {
// if so, add the fixed class
$('#kolonne-v').addClass('fixed');
} else {
// otherwise remove it
$('#kolonne-v').removeClass('fixed');
}
})
});
Description
This uses the jquery .on('scroll', handler) method, documentation here. The basic principal is that on document.ready you set the scroll point when your div becomes fixed to the top. Then you setup an .on('scroll', handler) event that triggers whenever the window is scrolled in. If the user scrolls to your point you add the fixed CSS class.